Star Trek: 10 Species Who Need To Get With The Times
1. The Humans
As Q, the Organians, and many others have said, humanity is improving quickly, but still has a lot to learn.
Humans have done a lot of evil stuff, alongside their aforementioned experiments on Changelings during the Dominion War. They continued to use artificial lifeforms like holograms and synths for unpaid labour, even after learning that Data, Voyager's Doctor, and many other artificial lifeforms could become sentient (not to mention all of the potentially sentient holograms killed daily on the holodeck). The Federation's ban on genetic manipulation could also be seen as a backwards policy, largely inspired by humanity's bleak history with Augments. In addition, the Human-dominated Section 31 has committed countless crimes against the Alpha Quadrant, manipulating the Romulans into joining the Dominion War, for example.
These problems persisted after the 24th century, and humanity later went through a period of increased isolationism after The Burn, eventually even leaving the Federation for a short time. Still, just like every other species on this list, we have the potential to be much better and learn from our mistakes.